scholarly journals Fabrication of Hybrid Surface Composite through Friction Stir Processing and Its Impression Creep Behaviour

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. Prakrathi ◽  
M. Ravikumar ◽  
K. R. Udupa ◽  
K. Udaya Bhat
Keyword(s):  
Activation Energy ◽  
Base Metal ◽  
Friction Stir Processing ◽  
Creep Resistance ◽  
Creep Mechanism ◽  
Stir Zone ◽  
Aluminium Matrix ◽  
Diffusion Creep ◽  
Impression Creep ◽  
Friction Stir

Al-Ni in situ surface composites were fabricated by friction stir processing method. Friction stir processing produced a composite with nickel and NiAl3 as reinforcement particles in aluminium matrix. The particles were fine and were in the submicrometer size range. The separation distance between the particles was very small. Impression creep experiments were conducted on the samples both at friction stir zone and base material zone at various temperatures. Steady state creep rates were estimated, and activation energy for creep was calculated. It is observed that the friction stir zone offered a higher creep resistance compared to the base metal zone. Higher creep resistance is attributed to the dissolution of nickel atoms into aluminium matrix and the presence of fine nickel particles and NiAl3 precipitates. The measured activation energy indicated that the associated creep mechanism is the dislocation creep in the temperature range of 30–150°C, both in friction stir zone and base metal zone. At higher temperatures (150–180°C) the diffusion creep mechanism is suggested.

scholarly journals Fabrication of Friction Stir Processed Al-Ni Particulate Composite and Its Impression Creep Behaviour

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Prakrathi Sampath ◽  
Vineeth Krishna Parangodath ◽  
Kota Rajendra Udupa ◽  
Udaya Bhat Kuruveri
Keyword(s):  
Activation Energy ◽  
Creep Rate ◽  
Base Metal ◽  
Creep Behaviour ◽  
Particulate Composite ◽  
Base Plate ◽  
Xrd Analysis ◽  
Maximum Temperature ◽  
Impression Creep ◽  
Friction Stir

Nickel powders were troweled on roughened Al base plate using a friction tool made from tool steel. Friction stir processing (FSP) was carried out using a load of 8 kN and with a tool rotation speed of 800 rpm and thus a surface composite was processed. Processed samples were characterized for revealing the microstructural features. SEM and XRD analysis revealed the presence of fine Ni particles in the stir zone which lead to a significant increase in hardness. Using the “refined energy model,” the maximum temperature developed within the processed zone was estimated and found to be around 275°C. Impression creep behaviour was assessed on both the base metal and processed zone at the temperature of 30, 100, and 200°C. Creep curves were generated and steady state creep rate (SSCR) values were found out to determine the activation energy. It is observed that friction stirred regions record higher creep rate values compared to the base metal. Estimated activation energy is in the range of 6 to 16 kJ/mol. Activation energy is marginally lower in the base metal compared to friction stir processed region.

MICROSTRUCTURAL PROPERTIES AND PHASE CONSTITUENTS OF 5A06 ALUMINIUM MATRIX SURFACE COMPOSITE FABRICATED BY FRICTION STIR PROCESSING

2011 ◽  
Vol 18 (05) ◽  
pp. 183-188
Author(s):  
LIU PENG ◽  
QING-YU SHI ◽  
YUAN-BIN ZHANG ◽  
SHU-BO XU
Keyword(s):  
Base Metal ◽  
Friction Stir Processing ◽  
Aluminium Matrix ◽  
Air Cooling ◽  
Friction Stir ◽  
Surface Composite ◽  
Ultrafine Grained ◽  
Matrix Surface ◽  
Average Grain Size ◽  
Amorphous Structures

A novel aluminium matrix surface composite added Al -based amorphous, whose layer depth was 5 mm, was fabricated by friction stir processing (FSP), at an air cooling. The surface composite region shows the obvious sandwich structure. It is considered to be a combination between the base metal and the amorphous strip via the FSP. The average hardness of the surface composite is about HV97, higher than the base metal is about HV80. The maximum tensile strength of the processed aluminium plate with the surface composite is 410 MPa. XRD results indicate that the constituent phases of the surface composite mainly include α- Al , Mg2Al3 , MnAl6 and La3Al11 Moreover, no obvious amorphous diffraction peaks are observed in the XRD results. However, a large number of ultrafine grained structures can be observed in the surface composite. The average grain size of them is ~90–400 nm constitutes the surface composite. These ultrafine grained structures are composed of the α- Al and α- Al amorphous structures.

Microstructural Evolution of Cast Mg-Al-Ca Alloy during Friction Stir Processing

2007 ◽  
Vol 539-543 ◽  
pp. 3739-3744 ◽  
Author(s):  
Da Tong Zhang ◽  
Mayumi Suzuki ◽  
Kouichi Maruyama
Keyword(s):  
Mechanical Property ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Base Metal ◽  
Microstructural Evolution ◽  
Friction Stir Processing ◽  
Stir Zone ◽  
Plate Surface ◽  
Friction Stir ◽  
Microstructure And Mechanical Property

A thixomoulded magnesium alloy containing thermally stable Al2Ca phase was friction stir processed, and its microstructure and mechanical property were investigated. In friction stir zone, the cast structure of the base metal is replaced by fine magnesium grains containing fine dispersoides of Al2Ca. Due to the refined grain size of 0.8-1 μm, hardness of friction stir zone is higher than that of base metal. Texture was developed at top and bottom surfaces, (0002) being parallel to the plate surface, whereas (0001) plane is randomly oriented in the center of friction stir zone.

scholarly journals Microstructural Analysis of Friction Stir Butt Welded Al-Mg-Sc-Zr Alloy Heavy Gauge Sheets

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 806 ◽  
Author(s):  
Tatiana Kalashnikova ◽  
Andrey Chumaevskii ◽  
Kirill Kalashnikov ◽  
Sergei Fortuna ◽  
Evgeny Kolubaev ◽  
...  
Keyword(s):  
Base Metal ◽  
Microstructural Analysis ◽  
Metal Flow ◽  
Sheet Thickness ◽  
Stir Zone ◽  
Layer By Layer ◽  
Friction Stir ◽  
Fine Grained ◽  
Grain Size Distributions ◽  
Zr Alloy

Friction stir welding (FSW) on a heavy gauge sheet of a hereditary fine-grained Al-Mg-Sc-Zr alloy was carried out to study the specifics of plasticized metal flow and microstructural evolution in different sections and zones of the joint. It was found that the stir zone (SZ) macrostructure may contain either a single or many nugget zones depending on the metal sheet thickness and the seam length. The effect of grain kinking in a thermomechanically affected zone (TMAZ) under pressure from the stir zone metal was discovered. The stir zone metal was fine-grained but had a microhardness lower than that of the base metal, which may be explained by the overaging effect of FSW on the Al3Sc precipitates. The tensile strength of the joint was almost equal to that of the base metal (BM). The grain size distributions were obtained in different sections below the sheet surface and away from the exit hole, which allowed us to suggest the specific adhesion-assisted layer-by layer metal transfer mechanism in FSW.

Mechanical Properties and Fracture Toughness of Aluminum Vessels by Friction Stir Welding

2004 ◽  
Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda ◽  
Masayuki Inuzuka ◽  
Hidehito Nishida
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Crack Initiation ◽  
Base Metal ◽  
Welded Joint ◽  
Stir Zone ◽  
Crack Initiation And Propagation ◽  
Friction Stir ◽  
Fine Grained ◽  
Initiation And Propagation

Mechanical properties and fracture toughness in friction stir welded joint of vessels of structural aluminum alloy type A5083-O are investigated. Welded joint from 25 mm-thick plate is fabricated by one-side one-pass friction stir. Charpy impact energy and critical crack-tip opening displacement (CTOD) in friction stir weld are much higher than those of base metal or heat-affected zone, whereas mechanical properties such as stress-strain curve and Vickers hardness do not have a conspicuous difference. Effects of microstructure on crack initiation and propagation are studied in order to clarify the difference of fracture toughness between stir zone and base metal. Both tensile test and bending test show that the fine-grained microstructure in stir zone induces to increase ductile crack initiation and propagation resistance by analyzing fracture resistance curves and diameter of dimples in fracture surface. It is found that high fracture toughness value in stir zone is affected fine-grained microstructure by friction stirring.

Microstructures and Properties of Biological Mg-Zn-Y-Nd Alloy by Friction Stir Processing

2013 ◽  
Vol 745-746 ◽  
pp. 33-38 ◽  
Author(s):  
Shi Jie Zhu ◽  
Li Guo Wang ◽  
Jin Jin ◽  
Jing Wang ◽  
Yu Feng Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Processing ◽  
Cast Alloy ◽  
Corrosion Current ◽  
Stir Zone ◽  
Grain Structure ◽  
Second Phase ◽  
Uniform Corrosion ◽  
Corrosion Properties ◽  
Friction Stir

In order to improve the mechanical properties and processing performance of the Mg alloys, and to prevent magnesium alloy from non-uniform corrosion and too fast degradation in the degradation process, the biological medical Mg-Zn-Y-Nd alloy was modified by the friction stir processing (FSP) technique in this paper. The microstructural evolution and phase constitute of the stir zone of Mg-Zn-Y-Nd alloy were investigated, the microhardness and the corrosion properties of the alloy after FSP process was studied. The results showed that the FSP parameters had significant influence on the stir zone and thermo-mechanically affected zone. The stir zone experienced severe plastic deformation and complete dynamic recrystallization after FSP. The stir zone consists of fine equiaxed recystallized grains, and thermo-mechanically affected zone (TMAZ) has deformed grain structure. The second phase distributed along grain boundaries in as-cast state was broken during the FSP and transformed into fine, uniform and dispersed particles in the grains. After FSP, the size of grains was reduced from 50μm (as-cast alloy) to 1-2μm. However, the second phase constitution didnt change. The alloy obtained good comprehensive mechanical properties after FSP. The microhardness of alloy after FSP increased from 39HV (as-cast alloy) to 64HV(FSPed alloy). The results of electrochemical tests in simulated body fluid showed that the corrosion potential of FSP alloy increased and corrosion current density decreased, which confirmed the uniform corrosion of FSPed alloy.

scholarly journals Influence of tool pin and shoulder geometries on microstructure of friction stir processed AA6063/SiC composites

2018 ◽  
Vol 19 (2) ◽  
pp. 211 ◽  
Author(s):  
Namrata Gangil ◽  
Sachin Maheshwari ◽  
Arshad Noor Siddiquee
Keyword(s):  
Friction Stir Processing ◽  
Particle Distribution ◽  
Combined Effect ◽  
Stir Zone ◽  
Friction Stir ◽  
Single Pass ◽  
Microstructure Examination ◽  
Sic Composites ◽  
Tool Pin

The present study investigated the combined effect of friction stir processing (FSP) tool pin and shoulder profiles on particle distribution and microstructure of AA6063/SiC composites. Two strategies were used, in first strategy, plain cylindrical, tapered cylindrical, square and triangular tool pin profiles were used with flat shoulder design. In second strategy square and cylindrical pin profiles were used along with clock-wise (CW) and anti clock-wise (ACW) scrolled shoulder design. Single pass processing was performed to fabricate the composites. Microstructure examination of sample processed with various pin profiles and flat shoulder design reveals that tool with square pin profile was most effective. Among other shoulder profiles, ACW scrolled shoulder resulted in pancake shaped stir zone (SZ) and exhibited significant improvement in SZ size, out of which ACW scrolled shoulder with cylindrical pin profile produced uniform particle distribution without any defects.

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